The Contributions of Chemistry to 
the Methods of Preventing 
and Extinguishing 
Conflagration. 

By 

Thomas H. Norton. 



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[Reprinted from the Journal of the American Chemical Society, 
Vol. XVII, No, 2. February, 1895.] 


THE CONTRIBUTIONS OF CHEMISTRY TO THE METHODS 
OF PREVENTING AND EXTINGUISHING CON- 
FLAGRATION . 1 

By Thomas H. Norton. 

Received December 24, 1894, 

I have felt it desirable on this occasion to direct your attention 
to a brief review of the services which the chemist has thus far 
rendered in the battle with fire, to the field of investigation still 
open, to the methods of testing and experimentation in this 
branch, and to the application of fact already gained to Ameri¬ 
can conditions. In the choice of this subject, I have, in common 

1 Abridged from the author's opening address before the Section of Chemistry of the 
American Association for the Advancement of Science, at the Brooklyn Meeting, 
August, 1894. 


2 THOMAS H. NORTON. METHODS OF 

with some of my predecessors, left the domain of pure science 
to consider more closely certain economic aspects of chemistry, 
and enter, to some extent, into the province of chemical engi¬ 
neering, which is now "ecognized in our leading schools as 
entitled to distinct and separate treatment. A further reason 
which has influenced me is the practical absence, to this time, 
in our works of reference, of any attempt to collate and classify 
the knowledge gained in this field. 

The total annual loss of insured property by fire is about 
$200,000,000, and of this sum nearly one-half occurs in the 
United States,—$90,344,075 in 1893. Foreigners marvel at this 
reckless disregard of the immense losses by fire shown by our 
countrymen, for from eighty to ninety per cent, of the 15,000 
fires which occur annually, can be traced to easily preventable 
causes,, and chiefly to faulty construction. Consider, for a 
moment, the tax which is being paid this Moloch. Our total 
loss of property amounts to one-fifth of the net profits of all the 
industries of the country. Propose to a trader or manufacturer 
cooly to throw one-fifth of the annual profits into the grate ! 
Yet this is what our productive industries, as a whole, have been 
and are doing in an unconcerned, if not cheerful, manner. The 
direct loss by conflagration is, however, not the only factor. 
Our fire departments and water supply cost us $30,000,000 
annually; while the loss of wages to mechanics and other pro¬ 
ductive forces, and numerous contingent amounts, swell the 
actual total loss to a most serious sum. The fire department .of 
Uondon costs but one-tliird of that of New York City; and the 
same ratio applies to most European cities. During a residence 
of ten years in French and German cities, I saw the fire engines 
called out but five times; while the average resident of an 
American city is apt to witness a call at least once a week. 
England’s annual fire bill is but little over $10,000,000. 

With these facts in view, is it not time to call a halt, to bring 
all the forces of science to bear in the battle, and redeem our 
America from what is nothing more or less than a servile bond¬ 
age? 

If we seek the reason for this vast difference in relative fire 
loss between the Europe of to-day and America, it is not to 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 3 

be found in a superiority of facilities for extinguishing confla¬ 
grations. The equipment of American fire departments is far 
better than that of the fire departments abroad. It results sim¬ 
ply from the fact that the European architect and builder have 
profited from the experience of the past, and learned that pre¬ 
vention is better than cure. The prevalent method of construe- * 
tion in New York is such, architects assure me, that the busi¬ 
ness part* of the city awaits only the proper combination of cir¬ 
cumstances to be the scene of a conflagration rivalling that of 
Chicago. 

Before leaving these general considerations, it should be said 
that there are many hopeful indications of an awakening from 
this apathy, and ample recognition should be made of the earn¬ 
est effort, inaugurated of late years in New England, to lessen 
fire risk ; the application of the so-called slow-burning principle 
of construction, especially to factories. By the adoption of this 
principle it has been possible to reduce insurance rates from one 
and one-half to two and one-half per cent, down to two-sevenths 
of one per cent. 

FIRE EXTINGUISHERS. 

Passing to the more specific treatment of the subject, we find 
that, as in medicine, so in the matter of protection against loss 
by fire there are two distinct lines of action : prevention and 
cure, or the adoption of such measures as to render an outbreak 
of fire difficult, and a conflagration practically impossible ; and 
the provision of the proper facilities for the rapid subjugation 
and limitation of fire under full headway. As in medicine, also, 
there is a growing conviction that the prophylactic treatment is 
the more important. It is hence particularly in this direction 
that the activity of the chemist has been chiefly called into play.. 

Eet us first briefly review the methods of extinguishing fire. 

In this field but little has been done to add to the efficacy of 
the agent used from time immemorial—ordinary water. In 
addition to its cheapness and universal distribution, water pos¬ 
sesses, over other liquids, peculiar advantages for the purpose in 
view—high specific heat and the formation of a vapor which is 
non-poisonous. Sulphur dioxide has been used to some extent; 
in fact it is an old-fashioned method in European countries to 



4 


THOMAS H. NORTON. METHODS OF 


extinguish burning chimneys by kindling sulphur on the hearth. 
A quicker production of the gas is effected, more particularly for 
use in confined spaces, by introducing receptacles of burning 
carbon disulphide; and cylinders of liquid sulphur dioxide, 
have, under similar circumstances, been successfully employed. 
The advantage in the use of this gas consists entirely in its 
exclusion of the air necessary to maintain combustion. The 
slower diffusion consequent upon high density renders it supe¬ 
rior for this purpose to other available gases. This advantage is, 
however, largely counterbalanced by its irritant, poisonous 
nature, and it has never been accepted as one of the recognized 
agencies of general application. 

Of much greater value is carbon dioxide, the efficacy of which 
is likewise based upon its ability to prevent the access of air to 
the material in process of combustion. The ease with which 
this is accomplished is shown by the familiar experiments of our 
lecture courses in chemistry. For practical results in dealing 
with ordinary fires, it is found best to employ a highly charged 
aqueous solution of the gas. Such solutions as those prepared 
for use as a beverage, have frequently been used in emergencies. 
One large soda-water establishment has been able to extinguish 
several fires in its own factory and in the neighborhood by the 
prompt use of the carbonated water in its receptacles. A quick¬ 
witted pharmacist recently extinguished a serious fire in his 
store from benzene, by quickly using a pailful of soda-water 
drawn from his own fountain, the case being one in which sim¬ 
ple water would have failed to accomplish the purpose. 

The so-called chemical fire-engines, now regularly used in our 
public fire departments, are all constructed upon the principle of 
charging a quantity of water when used with carbon dioxide and 
ejecting a stream of the carbonated water by the pressure of the 
gas itself. In the size most frequently employed the supporting 
truck carries two cylindrical tanks of steel or .copper, holding 
about eighty gallons of water and twenty-eight pounds of 
sodium bicarbonate with a leaden jar containing fourteen 
pounds of sulphuric acid. At the moment of using, by a simple 
mechanical device, the acid is admitted to the solution and a 
pressure of 140 pounds to the square inch is developed. The 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 5 

tanks are charged alternately while in operation so that it is pos¬ 
sible to maintain a continuous jet of one-fourth of an inch. The 
whole apparatus is light and easily drawn by two horses. There 
is also in use a combined manual and chemical fire engine 
devised by Foster. The pumps fill, with water, the compart¬ 
ments in which the chemicals are dissolved and whence the 
solutions come together in a generating chamber where the gas 
is evolved. Such engines are capable of throwing per minute 
thirty gallons of water containing 250 gallons of carbon dioxide 
to a distance of ninety feet. This type is also arranged for con¬ 
nection with high pressure mains. Very careful tests carried 
out in 1883 showed conclusively the great value of a small quan¬ 
tity of carbonated water in extinguishing fierce flame, especially 
in a confined situation and when combustion had not penetrated 
much beneath the surface. The same principle was applied 
earlier by Baragwanath and others in a variety of forms, to port¬ 
able extinguishers. Dick’s extinguisher, largely used in Eng¬ 
land, is a cylindrical tank of seven gallons, easily carried on the 
back, giving a pressure of from 70 to 120 pounds, and possess¬ 
ing a projectile range of fifty feet. The peculiar feature of this 
type is the storing of the sulphuric acid in a glass container, 
which is easily broken when the apparatus is to be used. Zabel’s 
apparatus, like Dick’s, is charged with sodium bicarbonate, but 
the acid used is contained in a cylinder from which it is liberated 
by simple inversion. Devices, essentially the same, have been 
introduced by Masnata and VanWisker. In Carter’s extin¬ 
guisher the sulphuric acid is replaced b)^ tartaric acid. 

Platt’s extinguisher has been successfully used for many 
years, and is valued on account of its simplicity ; the turning of 
a valve and the inversion of the apparatus bringing it at once 
into operation. Other efficient extinguishers of American origin 
are the Babcock, the Harkness, and the “ Climax.” In the lat¬ 
ter, sulphuric acid is replaced by oxalic acid, and in both the 
Harkness and “Climax” the carbonated solution is forced out by 
a pump. The Babcock extinguisher is filled with a solution of 
sodium bicarbonate, and has in its upper part a vessel of acid 
suspended by lateral pivots to a stirrup depending from the top 
of the apparatus. The stopper of this vessel is worked by a rod 


6 


THOMAS H. NORTON. METHODS OF 


through the top of the extinguisher. By withdrawing the stop¬ 
per, the vessel tilts over and mingles the acid with the solution 
producing at once the necessary pressure. 1 

The most recent and perhaps most efficient of chemical extin¬ 
guishers is that introduced in 1893 by Dr. Henry P. Weidig, 
and extensively tested throughout our country during the past 
twelve months. It is adapted not only for portable use, but also 
for replacing ordinary town engines and for permanent installa¬ 
tion in factories and on board ships, etc. 

The apparatus consists of a steel vessel containing liquid car¬ 
bon dioxide so arranged that it may be brought in connection 
with a receptacle filled with carbonated water, or a solution of 
ammonium carbonate, under any desired pressure. The carbon¬ 
ated wafer meets in its exit pipe with a stream of ammonia gas 
emanating from a cylinder of liquid anhydrous ammonia. The 
carbon dioxide is thus bound in the form of a soluble salt, ammo¬ 
nium carbonate. The solution thus formed is forcibly ejected, 
and, on reaching a fire, the heat not only volatilizes the water 
but decomposes the salt, so that a mixture of steam, carbon 
dioxide, and ammonia is the result. One volume of water 
will yield under these circumstances twenty-five volumes of the 
two latter gases. 

The principle of rapidly filling a confined space where 
fire has broken out with inert gases has been extended 
to the use of the gaseous products issuing from the. com¬ 
bustion under boilers. In certain industrial establishments 
devices are introduced by which the current of the mixture of 
nitrogen, carbon dioxide, and aqueous vapor can be directed, at. 
will, into a given apartment. The results are quite effective, 
combustion being promptly and permanently stopped. Other 
additions than carbon dioxide to the water used in extinguishing 
fires have proved of doubtful utility when submitted to practical 
tests. The list of such proposed additions includes potash 
(Kaiser), clay (Glaser), a mixture of sodium sulphite, and four 
parts sodium alum (patented 1884 in Austria, by Trotha, and 
sold in the form of cartridges), salt, alum, waterglass, copperas, 
Glauber’s salt, borax, magnesium chloride, sodium phosphate, 
and soda. 

1 Hexamer, Tournal of the Franklin Institute , August, 18,85. 


preventing and extinguishing conflagration. 7 

Ammonia gas alone has been recommended' Its lightness 
and irritant properties render it, however, much less efficient 
than carbon dioxide or sulphur dioxide. 

Hand grenades, 1 consisting of glass bottles, usually of a 
spherical form, charged with aqueous solutions of various chem¬ 
icals, have found their way of late years into somewhat extended 
use. They are conveniently arranged in the corridors of large 
buildings, and are intended for use in extinguishing incipient 
outbreaks of fire. The grenade is to be thrown with such force 
into the center of combustion that it breaks and scatters its con¬ 
tents upon the burning material. The salts present are supposed 
to act by either giving off incombustible gases or by incrusting 
the burning articles, thereby excluding air. In practice, how¬ 
ever, it is found that these grenades render but slight service, as 
they are frequently unbroken when thrown, especially against 
non-resistant substances. They are supposed to be charged with 
strongly carbonated water, or with a saturated solution of ammo¬ 
nium chloride, sodium chloride, sulphite, or thiosulphate. 
Analysis, however, shows quite a variety of composition in the 
contents. Sir Frederick Abel, 2 in 1881, found one to contain a 
strong solution of salt and waterglass. Geissler examined three 
current types with the following results: 3 

Hayward's Grenade .—Gross weight 1,120 grams; weight of 
liquid, 750 grams; composition, an aqueous solution of 15.7 per 
cent, calcium chloride and 5.6 per cent, magnesium chloride. 

Harden's Grenade .—Gross weight, 900 grams; weight of liquid, 
555 grams; composition, an aqueous solution of 19.5 percent, 
sodium chloride, and 8.9 per cent, ammonium chloride. 

Schonberg's Grenade .—Gross weight, 770 grams; weight of 
liquid, 440 grams; composition, an aqueous solution of 1.66 per 
cent, sodium carbonate, and 6.4 per cent, sodium chloride. 

It may be noted in passing that the salts in these grenades 
cost about one per cent, of their selling price. 

Finally, mention should be made of extinguishing powders, 4 
the use of which is literally a fighting of fire with fire. They 

1 Hexamer, loc. cit. 

2 Amer. Arch, 13 and 14. 

8 Phartn. Centrbl., 1885 , 447. 

4 Hexamer, loc. cit. 


8 


THOMAS H. NORTON. METHODS OF 


are well devised to produce, by rapid combustion at the expense 
of the oxygen in saltpeter, a sufficient volume of inert gas— 
chiefly sulphur dioxide and carbon dioxide—to prevent the cir¬ 
culation of air about a fire, and thereby cut off the supply 
of atmospheric oxygen for further combustion. Their appli¬ 
cation is, of necessity, limited to small enclosed spaces with¬ 
out many openings for ventilation, and they have been found 
chiefly valuable in drying rooms where easily volatile products 
are being driven off, as in connection with the manufacture of 
oilcloth. The ingredients are coarsely powdered and readily 
ignited. They are often packed in cartridges and provided with 
fuses. They burn without explosion, with a bright white flame, 
a strong odor, and much smoke. Bach pound yields about four 
and eight-tenths cubic feet of gas, which consists of two and 
three-tenths sulphur dioxide, one and one-tenth parts carbon 
dioxide, and one and four-tenths parts nitrogen. One pound 
•should be used for every 240 cubic feet of an enclosed space. 
The composition of the best known of these powders is as 
follows: 


Bucher's powder 

1 

kno 3 

S 

60 parts. 
36 “ 

1 

Heeren ’ s powder < 

{ 

[ 

c 

kno 3 

s 

c 

4 “ 

63 parts. 
29 “ 

4 “ 


{ 

Fe 2 0 3 

4 “ 


r 

kno 3 

58 parts. 
36 “ 



s 

Schweizer's powder < 

1 

c 

3 “ 


V. 

FeA i| “ 

SiO, (sand) 75 

1 

f 

KC 1 

20 parts. 

Gruneberg's powder <j 


kno 3 

s 

50 “ 

50 “ 

1 


Mn 0 2 

1 “ 

1 


Rosin 

10 “ 


kno 3 

60 parts. 

Zeisler's powder , 

1 4 

s 

36 “ 

I 


C and CaO 

4 ■■ 



PREVENTING AND EXTINGUISHING CONFLAGRATION. 


9 


Johnston’s powder 


Equal parts of KC 1 , KN 0 3 , 
Mn 0 2 and Rosin, moistened 
with waterglass and pressed 
into briquettes. 


Phillips ’ Fire Annihilator ( KN 0 3 60 parts, 

(introduced in 1851.) [ CaS Q 4 + ^.o's “ 

This latter was pressed in the form of a hollow brick. The 
central cavity contained sugar, and potassium chlorate and a 
vial of sulphuric acid, the latter so arranged as to be easily 
broken by a simple mechanical device. The brick was usually 
placed within a double cylindrical receiver containing water, so 
that the ignition of the powder caused not only the evolution of 
a large volume of gas, but also, by its heat, a liberation of a 
considerable amount of aqueous vapor. 

In reviewing this portion of our subject it would appear that but 
few opportunities are afforded the chemist for further contribu¬ 
tions of value. It would seem advisable, however, to study the 
feasibility of extending the use of carbon dioxide along lines 
similar to those in which automatic sprinklers have found such 
satisfactory application. In many factories and in numerous 
stores and warehouses the sprinkler, while most effective in 
quenching flame or hampering its progress, causes serious dam¬ 
age to manufactured products or materials for manufacture. 
The advantages of carbon dioxide over water under these condi¬ 
tions are manifest. It is not difficult to conceive of a system of 
piping, opening naturally at the level of the floor, through which 
either automatically or under the control of a watchman, a 
powerful current of the gas could be directed into any apartment 
where flame was apparent. In the many cases where the losses 
by water do and would naturally far exceed the losses by direct 
combustion, there is but little doubt that the use of the invisible, 
inert, harmless gas would enormously limit the destruction of 
valuable property. 

We come now‘to the most important division of our subject; 
namely, the methods of preventing loss or suffering by fire 
through the use of structural materials, textile fabrics, and the 
like, which are either entirely incombustible or slowly combusti- 


IO THOMAS H. NORTON. METHODS OF 

ble or from which the property of rapid combustion has been 
largely removed by special treatment. A structure built entirely 
of stone, brick, iron, cement, etc., is an illustration of the first 
type. A structure of brick with heavy beams of wood, heavy 
floors of plank, no hidden air-spaces, and a general absence of 
the lighter forms of woodwork, illustrates the second type,—the 
slow combustion construction. The third type is to be found in an 
edifice of wood, the component parts of which, either by impreg¬ 
nation or by suitable coatings, have lost the property of ready 
inflammability. 

The study of the choice of materials and their most efficient 
grouping as employed in the first and second methods of con¬ 
struction, apart from architectural considerations, falls purely 
within the domain of the mechanical engineer. It involves the 
question of strains and stresses under ordinary conditions and 
under the conditions of an elevated temperature. 

It is in the special field of rendering such easily combustible 
substances as wood and the vegetable fibers used in textile 
fabrics more or less resistant to flame that the chemist has been 
able to render service. 

Could our methods of building be limited to the completely 
fire-proof or the slow-burning system of construction, and inte¬ 
rior decoration and equipment be restricted to the use of non¬ 
combustible materials, it is evident that the chemist would have 
but little to do. But mechanical considerations, canons of taste 
and questions of outlay will, for a long time to come, sustain the 
extended use of wood in the erection and finishing of many 
classes of edifices, especially of our homes. The beginnings of 
our towns and cities are almost entirely in wood, and the same 
may be said of the suburbs of our centers of population. It will 
be many years before the rural residence and the home of the 
laborer in America will be as universally constructed of non¬ 
combustible materials as in Great Britain, France, Germany, 
and other European countries. In such a country as Japan it is 
almost impossible to imagine any general departure from the 
time-honored and picturesque national construction of bamboo. 
The restriction of fabrics to fibers of animal origin is likewise 
out of the question. 


PREVENTING and extinguishing conflagration. 


II 


In noting the historical development of the work of the chemist 
in the field as above outlined, we will first consider the methods 
which have been applied to textile fabrics and paper, and next 
those which have been used to render wood uninflammable. 

TREATMENT OF TEXTILES AND PAPER. 

The first experiments in this direction were made in England 
in 1735 by Obadiah Wild, 1 who secured a patent for rendering 
the cartridge cases used by the navy resistant to flame. This 
process consisted of the addition of a mixture of alum, borax, 
and copperas, to the paper pulp employed. Early in the present 
century the subject attracted the attention of several chemists. De 
Hemptine, of Belgium, in 1821, made quite an extended study of 
mixtures, similar to that of Wild, and other substances. At the 
same time Brugnatelli recommended the use of potassium sili¬ 
cate, Hermbstadt of ferrous sulphate, De Eisle of an unnamed 
compound. 1 Gay Lussac 2 was deeply interested in the subject. 
In 1830, as the results of his experiments, he recommended the 
use of various chlorides, phosphates, borates, tartrates, and car¬ 
bonates without, however, considering the difficulties involved 
in their application on a large scale. The employment of the 
alkaline carbonates was later urged strongly by Prater, while 
Fuchs 1 and Bethel in 1838 advocated waterglass and others, gyp¬ 
sum. Several patents were taken out during this * period by the 
different investigators. Still later Chevalier recommended the 
use of a mixture of borax and ammonium sulphate. The use of 
ammonium sulphate alone was proposed by De Breza in 1838, 
and that of ammonium chloride by Froggant in 1857. In 1855 
M. Solomon, 3 of Paris, submitted to the English Board of 
Ordnance a process for rendering canvas uninflammable. It con¬ 
sisted of immersing the materials for a day in each of the follow¬ 
ing baths : 

I. Aluminum sulphate, 30parts, II. Dry calcium chloride, 20parts 

Glue (gelatin), 10 “ Ckffce, s 10 “ 

Water, 60 “ ^ Water, 70 “ 

The interaction involved the 1 ¥hnation of gypsum and alumi- 

1 Versmatm and Oppenheim, Report to the British Association, 1859, 

2 Ann. chim. phys., 18, 211. 

3 Amer. Arch., 13 and 14. 


12 THOMAS H. NORTON. METHODS OF 

num chloride, which, in turn, precipitated the gelatin and con¬ 
verted it into a leatherlike insoluble substance. The object was 
to fill the pores of the fabric with gypsum and cover the surface 
with a hard binding material. Sir Frederick Abel, in reporting 
on the feasibility of this process found that it rendered the can¬ 
vas very difficult of ignition, but that it also gave to it a degree 
of rigidity and harshness which forbade its use. In 1856 Maug¬ 
ham 1 patented the use of ammonium phosphate and starch ; and 
in 1857 Thouret 1 patented the use of a mixture of three parts of 
ammonium chloride and two parts of ammonium phosphate, 
adopting these proportions on account of cheapness, although 
the ammonium phosphate alone gave most excellent results. 

During this period the importance of better protection for the 
scenery of theaters was recognized. After a serious fire in the 
Berlin opera house, the custom was inaugurated of soaking all 
scenery in a strong alum solution. 2 In 1857 a commission in 
Paris carefully examined the subject, and in accordance with 
their recommendations the order was issued to have all scenery 
in theaters impregnated with waterglass. 2 After the lapse of 
some years it was found that scenery thus treated possessed but 
slight resistant power. The explanation advanced is that the 
waterglass, on drying, contracts steadily until the solid particles 
finally sit very lightly on the yarn of the canvas. Another is 
that a solvent action is exercised by the water in the water-colors 
often used by scenic artists. It has been suggested by Hex- 
amer that the impregnation with waterglass could be advanta¬ 
geously followed by treatment with hydrochloric acid, thus pre¬ 
cipitating silicic acid directly in the fibers of the yarn, a process 
practically similar'to that of the use of mordants in dyeing. 

Versmann and Oppenheim, 3 in 1859, reported to the British 
Association for the Advancement of Science the results of an 
elaborate and extended study on the use of salts in treating 
fabrics, including some forty different substances in the range of 
their experimentation. Their tests were made on muslin free 
from starch, weighing 33.4 grams to twelve square inches ; and 
more in the direction of ascertaining the strength of the most 

1 Amer. Arch., 13 and 14. 

2 Fremy, Diet, de Chimie , 10. 

8 noc. cit. 


PREVENTING and extinguishing coneeagration. 13 

effective solution, rather than the weight of a given salt absorbed. 
After immersion in a solution the excess was removed by press¬ 
ing and not by wringing. Tests were conducted on a large 
scale in muslin works and laundries. None of the salts recom¬ 
mended to that time were found available where the operation of 
ironing was to be performed. Either a smooth surface could not 
be obtained, or the material was injured on the application of 
heat. 

The valuable results of Versmann and Oppenheim may be 
briefly summarized as follows : 

' KCN—very effective in a ten per cent, solution, but poisonous 
and expensive. 

Na 2 C 0 3 and K 2 C 0 3 —both very effective in a ten per cent, 
solution, but the one is efflorescent and the other deliquescent. 

NaHC 0 3 —very effective in a six per cent, solution, but car¬ 
bon dioxide is rapidly lost and the protective power disappears. 

Na 2 B 4 0 7 —very effective, but on warming, boric acid is liber¬ 
ated and attacks the fabric. 

NaOH—effective in eight per cent, solution. 

Na 2 S 0 4 —no effect. 

NaHS 0 4 —twenty per cent, solution is protective, but the 
stuff is gradually attacked. 

Na 2 S 0 3 —twenty-five per cent, solution is protective, but the 
.stuff is gradually attacked. 

Na 2 HP 0 4 —a saturated solution is effective, but the fabric 
becomes perfectly stiff. 

Na 2 Si 0 3 —the fabric is strongly attacked and the appearance 
affected. 

Na 2 Sn 0 3 —protective, but attacks the fabric. 

(NH 4 ) 2 00 —too volatile. 

„ (N—renders the fabric combustible. 

(NH 4 ) 2 B 4 0 7 —a five per cent, solution gives good protection, 
but the acid is easily liberated and corrodes. 

(NH 4 ) 2 S 0 3 —a ten per cent, solution is very effective, but the 
salt is deliquescent. 

NH 4 C 1 —a twenty-five per cent, solution gives excellent results, 
but stiffens the fabric. 

(NH 4 ) 2 HP 0 4 —gives excellent results alone or when mixed 


v 



14 


THOMAS H. NORTON. METHODS OF 


with ammonium chloride as in Thouret’s patent. Maughams 
mixture of this salt with starch was not available on account of 
uneven distribution throughout the mass. 

(NH 4 ) 2 SO—when rendered perfectly neutral by a-little ammo¬ 
nium carbonate, this yields the best results of all the ammonium 
salts. Chevalier’s mixture of this salt and borax attacks fabrics 
at a summer temperature. 


All these are good protectives, but attack 
the material. 


SnCl 

SnCl 4 

SnCl 4 2NH 4 Cl 

The following salts give good protection when used in solu¬ 
tions of the strength indicated, but are not available on account 
of price, or corrosive, or other properties; BaCl 2 fifty per cent, 
solution, CaCl 2 ten per cent., A 1 2 3 S 0 4 seventy-seven per cent., 
KAbSO, thirty-three per cent., NH 4 Al2S0 4 twenty-five per 
cent., FeS 0 4 fifty-three per cent., CuS 0 4 eighteen per cent., 
ZnS 0 4 twenty per cent., and ZnCl 2 eight per cent. 

Unsuccessful attempts were made to fix upon the fibers such 
protective salts as BaS 0 4 , A 1 2 (P 0 4 ) 3 , and various silicates. Zinc 
oxide and aluminum oxide gave good results, but would not 
adhere when washed. Antimony chloride was effective and 
withstood water, but not soap or soda. Stannous borate, phos¬ 
phate, and arsenate gave good protection and withstood washing, 
but gave a yellow tinge to the fabric. Zinc and calcium stan-, 
nates, while efficient protectors, would not withstand soap or 
soda. Stannic oxide was fixed permanently but imparted a yel¬ 
low color. It seemed to be well adapted for coarse material, sail¬ 
cloth, canvas, etc. 

For light stuffs, to be ironed, sodium tungstate was found to 
be the best agent, and the most effective solution is one of 28° 
Tw. or 1.14 sp. gr., containing also about three per cent, of 
sodium phosphate in order to prevent the formation and precipi¬ 
tation of the acid tungstate. 

Where the hot iron is not to be applied directly, ammonium 
sulphate can be advantageously employed in a ten per cent, solu¬ 
tion. The fabric is to be dried in chambers ; the ordinary colors 
on prints, except madder purple, are unaffected. 

Versmann and Oppenheim at first sought to produce, artifi- 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 


15 


daily, conditions similar to those existing in animal fibers such 
as silk and wool, which are not inflammable, and which contain 
about eighteen per cent, of nitrogen. Experiments to incorpo¬ 
rate nitrogenous substances such as glue or albumen into vege¬ 
table fiber were without practical result, although it was found 
possible by the use of urea to introduce into muslin thirteen per 
cent, of nitrogen, rendering it thereby uninflammable. 

Essentially the same object is obtained, as we have seen, by 
the use of ammoniacal salts. 

Sir Frederick Abel 1 made reports in 1859 and i860 to the Eng¬ 
lish Ordnance Department on Versmann and Oppenheim’s results, 
especially with reference to the protection of canvas. The advan¬ 
tages of sodium tungstate for light fabrics were fully confirmed 
by him. The availability of stannic oxide for sail-cloth was like¬ 
wise confirmed. Sail-cloth was most effectively deprived of its 
inflammability thereby, and the protective agent was perma¬ 
nently fixed in the fabric, being affected neither by friction nor 
by repeated washing, while the strength of the canvas was not 
diminished. The only objections to the use of stannic oxide 
were: First, the notable increase in weight amounting to fifty per 
cent, of the original weight of the canvas; and, second, the com¬ 
parative costliness. While the first objection was regarded by 
Abel as practically inseparable from the permanent fireproofing 
of fabrics, the second he considered much more serious. 
Accordingly, we find him, shortly after, patenting and submit¬ 
ting to the Ordnance Department, a cheaper process for fire¬ 
proofing canvas, consisting of the deposition in the fiber of a 
double sodium and lead silicate. Boiling solutions of basic lead 
acetate and of waterglass were used. I have not been able to 
ascertain how extended a use was made of this process. Abel 
in his reports states that he finds saturation with a solution of 
waterglass alone an efficient protective ; but that its value is 
temporary only. He sums up the difficulties to be encountered 
in fireproofing fabrics as follows : 

(1) The protective material renders the fabric harsh and 
rigid; or (2) it absorbs moisture and keeps the fabric damp ; 
or (3) it affects the strength and durability of the fabric ; or (4) 


y 


1 Amer. Arch., 13 and 14. 


16 THOMAS H. NORTON. METHODS OE 

it is easily detached by rubbing or shaking; or (5) it is soluble 
in water and must be renewed after wetting. 

In 1870 Abel 1 recommended to the Ordnance Department treat¬ 
ment with calcium chloride for rope mantelets on board warships 
in order to keep them damp and prevent ignition during the fir¬ 
ing of guns. 

In 1871 the Austrian chemist Patera 2 introduced the use of 
magnesium borate as a protective for fine fabrics and delicate 
colors. The materials are soaked in a bath of three parts of 
borax and two and one-half parts of magnesium sulphate in 
twenty parts of water with the necessary amount of starch, then 
wrung between cloths and dried. For coarser stuffs he found 
mixtures of ammonium sulphate and gypsum effective. 

In 1882 a special committee of the Franklin Institute of Phila¬ 
delphia reporting on safety devices for theaters, gave the results 
of their experiments on the fireproofing of scenery and gauze. 1 
They obtained the best results with the material devised by Dr. 
J. Papen, of Frankfort, Germany. The details of its composi¬ 
tion are not given, but it has rendered excellent results in the 
Frankfort opera house, yielding efficient protection, not alter¬ 
ing in time, nor affecting the strength or color of the fabrics, and 
producing no injurious effect on the voices of singers or actors. 
The committee obtained also very good results from the use of 
ammonium sulphate, of silica precipitated on the fiber, and from 
the processes of Gantsch and Judlin, details of which are also 
lacking. 1 

This question of fireproofing scenery, etc., in theaters had 
already been the subject of considerable investigation. In 1877 
a committee of the House of Commons took evidence on the 
matter, and we find Mr. Henderson, of the Criterion theater tes¬ 
tifying that he used regularly sodium tungstate in the prepara¬ 
tion of new scenery ; although it was not available for old 
scenery. 

A committee of the Tondon Society of Arts, 1 in 1883, made a 
report on the same subject, recommending sodium tungstate as 
the best safeguard for scenery. They found on investigation, 

1 Amer. Arch., 13 and 14. 

2 Flammenschutzmittel, Wien, 1871. 


preventing and extinguishing conflagration. 17 

that the scenery in nearly all Tondon theaters was treated with 
some fire-proof preparation; most having as a basis a borate or a 
silicate. They add in their report: “these compositions do 
not prevent the evolution of gas when an article is exposed to 
sufficient heat; and the gas takes fire and burns. When the 
external source of heat is removed, no more gas is evolved, and 
combustion ceases. Prepared articles burn when exposed to 
sufficient heat, but do not support combustion. One effect of 
this is that it is very much more difficult to set such materials on 
fire; and this either prevents the breaking out of the fire, or 
renders it much more easy to deal with when broken out.” 

The theaters of Paris had already used largely for protecting 
scenery, a solution of the following composition devised by Mar¬ 


tin and Tessier: 1 

Ammonium sulphate. 8 

Ammonium carbonate. 2 

Boric acid. 3 

Borax. 1 

Starch. 2 

Water. 100 


Among recently introduced preparations for the purpose in 
view, the efficacy of which has not been fully tested, are the fol¬ 
lowing : 

Vendt and Herard, 2 1885. A solution of eight parts ammo¬ 
nium chloride, ten parts ammonium sulphate, two and one-quar¬ 
ter parts sodium thiosulphate, four and one-half parts borax, 
and seventy-two parts water. 

Winckelman : 3 —Manganese chloride. 33 parts. 

Glacial phosphoric acid... 20 “ 

Borax. 10 “ 

Magnesium chloride. 12 “ 

Magnesium sulphate. 25 “ 

Fabrics are boiled for six hours in this solution and become 
thoroughly impregnated with insoluble double salts. 

Martin and Tessier : 3 —Boric acid. 6 parts. 

Borax. 3 “ 

Ammonium chloride. 15 “ 

Water. 100 “ 

1 Fr£my, Diet, de Chimie , 10. 

2 Genie civ., 6, 227. 

s Sc. Amer. Cyclop, of Receipts, p. 217. 















j8 THOMAS H. NORTON. METHODS OR 

Used chiefly for cordage, sail-cloth, canvas, and straw, the 
materials being steeped in the solution. 

Vogt i 1 —Ammonium chloride. 2 parts. 

Zinc sulphate. 1 

Water. 20 

Starch as needed. 

Subrath: l —Alum.* * 5 

Ammonium phosphate. 5 

Water. 9° 

Hattin : x —Calcium dihydrogen phosphate, ammonia, and 

gelatinous silica. . . 

Pereles : x —Combined solutions of sodium phosphate, silicate, 

and tungstate. 

Nicoll: 1 —Solution of alum, borax, sodium tungstate, and 
dextrin, or equal weights of calcium acetate and chloride in hot 
water. 

These comprise the processes for the protection of fabrics 
introduced up to the present time. As is easily seen, the use of 
sodium tungstate, the borates, or ammonium salts alone or in 
mixtures is the striking feature. 

A few words with regard to the methods of manufacturing or 
protecting paper are here in place. 

Martin and Tessier 1 used the following bath for paper whether 

printed or unprinted. 

Ammonium sulphate. • • 8 parts. 

Boric acid. 3 “ 

Borax. 1.7 “ 

Water. 100 “ 

The solution is placed in a vat, at the end of the paper-mak¬ 
ing machine and kept at 50° C. 

Paper thus treated is non-inflammable. The value in many 
kinds of business of a totally incombustible paper is easily appre¬ 
ciated ; and several varieties, all based on a large use of asbes¬ 
tos, are in vogue. T. Frobeen’s paper is made from ninety-five 
per cent, of asbestos and five per cent, of wood-pulp mixed in 
water containing borax and glue. For ink he uses a mixture of 
platinum chloride andindia ink. 

Halfpennig’s paper 1 is made from one part vegetable fiber, 

1 Sc. Amer, Cyclop, of Receipts, p. 217. 











PREVENTING AND EXTINGUISHING CONEEAGRATION. 


two parts asbestos, one-tenth part borax, and one-fifth part alum, 
formed in the ordinary way into a pulp to which waterglass is 
sometimes added. A paper of great flexibility and strength is 
obtained by coating sheets of linen on both sides with the 
incombustible paper. His ink is a mixture of graphite, copal, 
copperas, and indigo sulphate. 

Paper is also made from pure asbestos and from asbestos 
mixed with alum, aluminum sulphate, zinc chloride, and resin 
soap. 

A fire-proof writing-ink is an ammoniacal solution of silver 
nitrate, with a little india-ink, while platinum chloride mixed 
with lamp-black and varnish is employed as a fire-proof printing- 
ink -‘ 

methods for rendering wood INFEAMMABEE. 

In taking up next, the history of the efforts to render wood 
non-inflammable we encounter two distinct methods of procedure. 
The first is impregnation by the solutions of the chemical com¬ 
pounds which are to be operative, and includes such variations 
as the precipitation of insoluble salts within the wood by double 
decomposition ; the second is the covering of the exterior of 
wood by protective coatings. In the case of existing structures, 
the latter is evidently the only means available. 

The first recorded effort to protect wood was made at Munich in 
1823, during the rebuilding of the Royal opera house after 
destruction by fire. 2 On the recommendation of Professor Fuchs 
all of the woodwork then received several coatings of waterglass. 
The surface covered was 400,000 square feet, and the cost was 
$1,000, or at the rate of $1 for 400 feet. Professor Fuchs pre¬ 
pared his solution by treating ten parts of caustic alkali, fifteen 
parts of infusorial earth, and one part of charcoal, with water. 
A somewhat similar composition was also in vogue then in Eng¬ 
land. It was made by grinding in oil one part of fine sand, two 
parts of wood-ashes, and three parts of slaked lime, and was 
applied with a brush. Fuchs’ protective kept well, and was 
regarded as effective for twenty years, but later tests showed that 
its chemical composition was materially changed, and it no 

1 Sc Amer. Cyclop, of Receipts, p. 217. 

2 Rymer-Jones, Eel. Eng. Mag., 33 . 55 . '885 ; Hexamer,/owr. of the Frank. Inst., 114,125. 


20 


THOMAS H. NORTON. METHODS OF 


longer afforded security. It may be mentioned here that it was 
not then found available for scenery on account of the gloss it 
imparted. During this period the following mixtures came into 
vogue, chiefly for external protection, as m the case of shing e 
roofs: three parts of wood-ashes and one part of boiled linsee - 
oil; three parts of alum and one part of copperas; ashes and 
lime with skimmed milk as a binding material. 

In 1841 Payne 1 introduced his combined process for rendering 
wood not only uninflammable, but also proof against wet and dry 
rot and insects. It consisted in the precipitation throughout the 
mass of a piece of timber, of barium or calcium sulphate by 
double decomposition. In carrying out the process, wood is intro¬ 
duced into a capacious cylinder, the air is drawn out by steam, and 
a solution of barium or calcium sulphide is injected into the partial 
vacuum; the cylinder is exhausted again and then completely 
filled with the solution of the sulphide; pressure is increased to 
140 pounds per square inch, and after an hour the solution is 
drawn off. The operation is then repeated, use being made of a 
solution of copperas; as a result the pores of the wood are largely 
filled with the insoluble sulphate and it becomes hard as stone. 
The soft, porous, cheaper grades of wood are thus rendered equal 
in point of durability and strength to the hardest varieties of 
timber. Wood prepared in this way is largely used in England 
in connection with public works and railways. 

At about this period several processes were introduced for the 
preservation of wood against decay ; and claims were made that 
these were also valuable for rendering wood uninflammable. 1 
These processes consisted essentially in the introduction into the 
pores of wood of metallic salts in solution, which combined with 
the nitrogenous matter present to form insoluble, non-fermentable 
compounds, and therefore removed sources of decay. 

The chief methods employed were kyanizing or impregnation 
with mercuric chloride; burnettizing or impregnation with zinc 
chloride, using a three per cent, solution; boucherizing or injec¬ 
tion of copper sulphate, using a one per cent, solution; and 
Beer’s process of impregnating with borax. All of these meth- 


iRymer-Jones, Eel. Eng. Mag., 33, 55, 1885. 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 21 

ods give partial protection against combustion. With regard to 
their availability, expense and the evolution of poisonous vapors, 
when exposed to heat, militate against the use of corrosive subli¬ 
mate. Copper sulphate, which can be absorbed to the extent of 
twenty kgms. per cubic meter of wood, is far inferior to many 
other salts as a fire protective; it colors the wood blue when 
exposed to atmospheric conditions, and in common with the mer¬ 
curic salt, corrodes iron nails and bolts. Zinc chloride is more 
efficient, although in common with the two preceding salts it 
affects the tenacity and elasticity of wood. Borax seems to be 
more free from the objectionable features just enumerated, and 
more recent experiments have shown that its protective power is 
far superior to that of the copper or zinc salts, although inferior 
to that of sodium tungstate and ammoniacal salts. 

The operation of impregnation in closed vessels by the use of a 
vacuum was devised by Samuel Bentham in 1794. It was suc¬ 
cessfully employed in France by Breant and Bethel in 1830, and 
later in England for the purpose of kyanizing and burnettizing, 
as well as in connection with Payne’s process. 1 In boucheriz- 
ing, the copper sulphate solution is usually forced longitudinally 
from the butt to the trunk of a tree, just after it is felled, by an 
ingenious arrangement, involving the use of rubber caps and an 
elevated tank. 2 

In 1855 Salomon’s process 3 of treatment with aluminum sul¬ 
phate and calcium chloride, already described in connection with 
textile fabrics (p. 147) was applied to wood with some little suc¬ 
cess. 

During this same year Maugham’s process 3 of treating wood 
with a mixture of sodium phosphate and ammonium chloride, 
and Jackson’s process, based on the combined use of zinc and 
ammonium salts, were both submitted to critical tests by Sir 
Frederick Abel, 3 who found neither as cheap or as efficient as 
sodium silicate. Abel reported at length to the English Board 
oi Ordnance on the advantages offered by th^ use of sodium sili¬ 
cate, which he had recommended at an earlier date for use in the 


1 Fremy, Diet, de Chimie , 10. 

2 Rymer-Jones, Eel. Eng. Mag., 33, 55, 1885. 
Umer. Arch., loc. cit. 


22 


THOMAS H. NORTON. METHODS OR 

Crimea to render huts fireproof, and which was used in 1856 m 
camp huts at Aldershot for the Royal Engineers. By applying 
first a coat of silicate, then a coat of lime, and finally a second 
coat of silicate, Abel obtained a covering which resisted rain and 
showed no tendency to crack, shrink, or detach itself from the 
wood. The cost was one cent for five square feet. Eater reports 
to the board made by Abel in 1870 and 1872 state that the effi¬ 
ciency of this protective was totally unaffected by time. In 1881 
he also reports that sodium tungstate, already employed for fab¬ 
rics, may be successfully used for wood, but that it offers no 
advantages over the sodium silicate process. It is absorbed by 
wood at the rate of fifty-six kgms. per cubic meter. 

Patera, who studied the subject very extensively, recommended 
in 1871, 1 the use of magnesium borate for wood, finding it fully 
equal to sodium tungstate. He urged also very strongly the use 
of a mixture of one part strong ammonia and two parts gypsum, 
especially for roofing. Severe tests applied to this protective 
yielded such satisfactory results that the Austrian Minister of 
Finance recommended it for all government buildings- where 
woodwork was exposed. Patera also advises the use of a coat¬ 
ing of one part of ammonium sulphate, two parts gypsum, and 
three parts water. Another protective covering recommended 
by him is obtained by first coating wood twice with a saturated 
solution of three parts of alum and one part of copperas, and 
then applying a coat of clay mixed in copperas solution. 

The successful use of sodium silicate led to the employment of 
various siliceous paints. One devised by Vilde and Schambeck 2 
seems to-have given good results. Its composition is pulverized 
glass twenty parts, pulverized porcelain twenty parts, pulverized 
stone twenty parts, quicklime ten parts, waterglass thirty parts. 
The thick syrup is applied with a brush and hardens quickly. 

Ransome’s siliceous paint, 3 introduced in 1871, consisted of a 
mixture of pure quartz and waterglass. After application it was 
coated with calcium chloride in order to render it perfectly insol¬ 
uble. It has not been used of late years. 

Another process involves the application of three coats of dilute 

llyOC. cit. 

2 Sc. Amer. Cyclop, of Receipts, p. 217. 

SAmer. Arch., loc. cit. 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 23 

waterglass, then of two coats of the same mixed with powdered 
glass; finally of one of thick waterglass. 1 Other preparations 
consist simply of more or less dilute waterglass, to which zinc 
oxide or ferric oxide has been added. 1 A most important modi¬ 
fication of the simple silicate is that known as cyanite 1 and pre¬ 
pared by introducing aluminum hydroxide into waterglass, so 
that it is practically a basic aluminum silicate. It is a perfectly 
colorless liquid, and is applied with a brush. The cyanite is 
manufactured in England, and is employed in the English War 
Department by the Woolwich Arsenal, and by the Department 
of Railroad Inspection. That the product is variable would be 
indicated by Helbig’s analysis 2 in 1888, when he found nothing 
present but waterglass. 

Among other recent preparations is the ignifuge of Martin 3 of 
France (1880) used for impregnation, and composed of ammo¬ 
nium chloride fifteen parts, boric acid six parts, borax three 
parts, water 100 parts. 1 Another French preparation is that of 
Vendt and Herard, 4 1885, also for impregnation. It consists of 
alum twelve parts, borax five parts, sodium thiosulphate three 
parts, potassium sulphate ten parts, water seventy parts. Some¬ 
what peculiar are the following combinations, also used in 
France ; 5 the first a solution of lead sulphate in neutral tartrates; 
the second an ammoniacal solution of a mixture of calcium ace¬ 
tate and calcium chloride. Brocher’s preparation, 1 manufactured 
near Dresden, and used to some extent in Germany, is of 
unknown composition, and involves the use of three different 
liquids in the course of the application of the several coats. 
Objection has been made to it for this reason, as well as on 
account of the tendency of the solutions to solidify before use. 

The general recognition of the utility of protective coatings led 
gradually to the extended use of asbestos. E. G. Erichsen, 6 of 
Copenhagen, in 1881, devised a new protective which consisted of 
a soluble silicate, metallic oxides, and lime, with ten to twenty 

1 Boudin et Donny, Rapport. 

^ . 2 Archiv. f. Hygien, 1888 , hi. 

3 Troost, Bull, de la Soc. d'Encouragement, 1880, p. 384. 

4 Genie civ., 6, 227. 

5 Fr£my, Diet, de Chimie , 10. 

6 Amer. Arch., loc. cit. 


24 THOMAS H. NORTON. METHODS OF 

per cent, of asbestos. It was applied with a trowel and formed 
a sort of fire-proof enamel which could be washed with water. 
Erichsen’s preparation was extensively used in Europe, both on 

the continent and in England. • ^ 

A further step forward was made in 1883, by C. J. Mountford, 
of Birmingham, England, who brought out a preparation which 
consisted of asbestos ground and reground in water, sodium or 
potassium aluminate and waterglass. When liable to exposure 
to atmospheric agencies, it receives, further, a certain amount of 
oil driers and gummy matters and sometimes zinc oxide or barium 
sulphate. The United Asbestos Co., of England, has manufac¬ 
tured this product on a large scale for ten years, and it has been 
extensively employed, especially in England. Among other 
important edifices treated with it are the Parliament Buildings, 
the British Museum, South Kensington Museum, the Crystal 
Palace, various theaters, Royal palaces, etc. The cost of this 
material is eighteen cents per kilogram, and 100 kgms. suffice to 
cover, with three coats, a surface of fifty-four square meters, so 
that the cost per square meter is about thirty-three cents. It is 
a thick, gray product, easily applied, presents a satisfactory 
appearance when used alone on wood, and furnishes an excellent 
basis for the application of other paints. 2 

This represents probably the best type of protective coating, 
thus far devised. There are also two other English preparations 
of some repute, the nature of which is apparently analogous to 
the above; Bell’s asbestos paint and Blane’s fire-proof and 
water-proof paint ; 2 while, in America, a single firm manufactures 
an asbestos paint. 

Such is the history of the different methods of restricting the 
combustion of wood which have been presented during this cen¬ 
tury. 

Eet us next note the means devised to test comparatively the 
value of the diverse materials recommended. 

TESTS FOR FIRE-PROOF PREPARATIONS. 

In Versmann and Oppenheim’s extended investigation on pro- 
tectives for textiles, 3 the study was carried on in such a way as 

1 Amer. Arch., loc. cit. 

2 Boudin et Donny, Rapport. 

3 Report to the British Association, 1859. 


preventing and extinguishing conflagration. 25 

effectually to eliminate one after another of the salts experi¬ 
mented upon until a small group was left, the efficiency of each 
member of which, under varying conditions, was satisfactorily 
demonstrated. The usefulness of impregnation by sodium tung¬ 
state is easily illustrated by exposure to a flame of strips of cotton 
cloth, some of which have been soaked in a tungstate solution, 
while others are in the ordinary condition. The merits of the 
different protectives for wood, as each one in turn came before 
the public, until a recent date were usually tested by application 
to a small hut or the like, within which an active fire of very 
combustible material was started. Such was the custom of Sir 
Frederick Abel 1 in his series of experiments already referred to. 

Some thirty years ago Professor Pepper, of Tondon, made com¬ 
parative tests on four salts, strongly recommended for impreg¬ 
nating wood, and as a result placed them in the following order, 
the most efficient first: 2 

1. Ammonium phosphate. 

2. Sodium tungstate. 

3. Borax. 

4. Alum. 

The most thorough and valuable study in this field was made 
in 1887 by two Belgian chemists, Professors Boudin and Donny, 
of the University of Gand (Ghent) at the request of the Belgian 
Minister of Public Works. 3 They submitted to rigorous com¬ 
parative tests all of the preparations then in vogue, some nine¬ 
teen in number, and it is to be regretted that their exhaustive 
report has not been reproduced in toto in our journals. 

P. Uochtin, 4 in 1893, introduced a simple and easy, if not per¬ 
fectly exact method of testing, which he applied to about fifty 
chemical compounds, and brought out several interesting facts. 

We will consider first his more elementary methods, taking up 
later the more improved ones of Boudin and Donny. 

Uochtin used strips of thick filter-paper fifty cm. long and five 
cm. broad, which are soaked in solutions of the substances sub¬ 
mitted to experiment, usually a series for each substance of five- 

1 Amer. Arch., loc. cit. 

2 Sc. Amer. Cyclop, of Receipts, p. 217. 

3 Rapport sur les proc£d6s destines & assurer l’ininflammabilit6 des bois, Gand, / 887 . 

4 Dingier's poly. Jour ., 290, 230. 


26 


THOMAS H. NORTON. METHODS OF 


tenths, one, two, three and five-tenths, five, ten, fifteen, and 
twenty per cent, solutions of the anhydrous compound. After 
being hung on lines and drying at ordinary temperature, the 
lower ends, where greater quantities accumulate, are clipped off. 
When insoluble precipitates are to be obtained in the paper, it is 
first soaked in a solution of the soluble salt, then dried, then 
soaked in a solution of the precipitating reagent, dried, washed, 
soaked for six to twelve hours in water, washed, and finally dried. 
The strips are then folded lengthwise, and while held horizon¬ 
tally, with the folds beneath, kindled at one end. Observation 
then shows whether the foreign substance hinders or helps com¬ 
bustion, and what is the minimal relative weight of a salt or the 
minimal strength of its solution, necessary to render the paper 
uninflammable. 1 

Experiment indicates that different substances, although in 
solutions of equal strength, are retained unequally by the paper; 
the amount retained increasing in proportion to the insolubility 
or ease of crystallization of a compound. Very soluble substan¬ 
ces, are absorbed in almost equal proportions. It is also worthy 
of note that apart from compounds which are practically store¬ 
houses of oxygen, as the chlorates, there are substances which 
distinctly favor combustion, the alkaline sulphates for example. 
As illustrations of Eochtin’s method, a strip soaked in a twenty 
per cent, solution of sodium sulphate is kindled at one end. It 
is observed that it burns easily and readily to the end, as readily 
as if no foreign matter were present. Again, four strips of paper 
soaked in ammonium chloride solutions, a in a twenty per cent, 
solution, b in a five per cent, solution, c in a two per cent, solu¬ 
tion, and d in a one per cent, solution, are in turn held in the 
flame. No propagation of flame is shown by a; b shows a small 
flame, which is extinguished quickly on removal from the source 
of heat; c yields a larger flame, which burns for about five cm. 
after removal; and d furnishes a still larger flame, which burns 
to the end. It is evident that the use of a two per cent, solution 
affords partial protection, and of a five per cent, solution, full 
protection against inflammability. I have found in personal 
experience an advantage in using for elementary tests the thin 
slips of pine wood about eight cm. long and one cm. wide, easily 

1 Dingier's poly .Jour., 290, 230. 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 27 

obtained from any tobacconist. These are preferable to L,och- 
tin’s strips, as they can be used for testing protective coverings 
as well as solutions; and in the case of the latter the distribution 
of the foreign substance throughout the strip is more uniform. 
The experiments conducted before you, illustrate the relative 
resistance imparted by a number of the preparations already 
enumerated. 

A third method of comparative testing was devised by Boudin 
and Donny. 1 A cylinder of light iron rods forty cm. long and 
twenty-five cm. in diameter is mounted upon an horizontal axis 
so that it can be easily kept in rotation. Beneath this cylinder 
is a series of five Bunsen burners, consuming 1000 liters of gas 
hourly. The wood used for the experiments is in the form of 
rectangular sticks thirty-nine cm. long and fifteen mm. square. 
After treatment by injection or painting, bundles of four sticks 
of each preparation—the individual sticks kept apart by light 
wedges—are attached by wire to the rods of the cylinder, parallel 
to its axis, and at equal distances from each other. A bundle 
of sticks which have not been treated serves as point of compar¬ 
ison in each charge of the cylinder. The row of lamps is next 
lighted, and the cylinder turned at the rate of six revolutions per 
minute, so that all of the bundles are uniformly and evenly 
exposed to the action of the flame. The time is then noted at 
which each bundle takes fire, or is seriously affected by the heat; 
and when the combustion of a bundle becomes sufficiently active 
to affect its neighbors, it is removed. As an example of the 
working of this method the following series of tests may be quo¬ 
ted from the Belgian report: 

Wood not treated took fire at the end of one and three-fourths 
minutes. 

Wood treated with zinc sulphate or alum, at the end of three 
and one-half minutes. 

Wood treated with ammonium sulphate or copper sulphate at 
the end of five minutes. 

Wood treated with borax, or boric acid, or Martin’s ignifuge, 
or Brocher’s preparation, at the end of eight minutes. 


1 Rapport. 


28 


THOMAS H. NORTON. METHODS OF 


Wood treated with sodium tungstate, at the end of ten minutes. 

Wood treated with calcium chloride or ammonium chloride, at 
the end of fifteen minutes. 

Wood treated with waterglass alone, or with lime, or with 
powdered glass and kaolin, or cyanite, or the Bell, Blane, or. 
United Asbestos Co. preparations, or ammonium phosphate, at 
the end of thirty to forty minutes. 

The two latter were charred throughout without the produc¬ 
tion of flame. 

A still more rigorous and decisive test has been devised by 
Boudin and Donny, 1 one which places the experimenter as nearly 
as possible in the conditions which ordinarily precede the out¬ 
burst of a conflagration; viz the production of a flame of 
greater or less intensity in immediate contact with inflammable 
material; such as happens when an oil lamp is overturned, a box 
of matches is kindled by the gnawing of an inquisitive rat, or the 
like. 

The test is simple in its nature, and depends, as in the prece¬ 
ding method, upon the use of wooden rods subjected to a pro¬ 
tective treatment. A convenient size is that of twenty cm. in 
length and fifteen mm. square. Thirty-six rods of the same 
preparation are used to form a small open construction by sim¬ 
ply superimposing rows of six alternately crossed upon each 
other, leaving in the center an open spacfe about six cm. wide 
for the reception of burning material. The whole arrangement 
is one permitting of the freest possible circulation of air, a con¬ 
dition which is further aided by placing the construction upon a 
piece of heavy wire gauze, supported upon two bricks. Little 
bundles of splints, weighing thirty-five grams each, are used as 
sources of combustion. They are introduced into the central 
space, lighted, and the result carefully noted. If combustion be 
not communicated to the construction by the burning of a single 
charge, a second is added, and so on. It is easily seen from the 
series of experiments with these constructions carried on before 
you, that this method of the two Belgian chemists is of the most 
searching and exacting nature, and yields comparative results of 
the highest value. 


1 Rapport. 


PREVENTING AND EXTINGUISHING CONFEAGRATION. 29 


In such a series of tests, for example, a construction of ordi¬ 
nary wood takes fire at the end of one minute, is in complete 
combustion two minutes later, and at the end of ten minutes 
leaves a mass of ashes. Wood treated with ammonium chloride 
takes fire at the end of three minutes and undergoes complete 
combustion. Wood covered with cyanite takes fire at the end of 
three minutes and burns slowly for fifteen minutes, leaving the 
exterior intact. Wood treated with three coats of waterglass 
stands exposure to four successive charges of combustible, with 
but little evidence of the propagation of fire, although the surface 
of the rods is deeply altered by the exudation and swelling of 
the silicate. Wood treated with ammonium phosphate, or the 
United Asbestos Co. preparation, is scarcely affected after four 
successive charges. The construction remains intact with the 
interior slightly charred. 


RESUETS THUS PAR ATTAINED. 



Reaving the methods of testing, let us now briefly summarize 
the results of experiment, and experience with fire protectives 
up to the present date. For textile fabrics, sodium tungstate 
and magnesium borate yield, unquestionably, the best results, 
when materials are to be ironed, while ammonium phosphate or 
sulphate is preferably used in other cases. 1 

The use of the tungstate, especially, is widespread in England. 
It may be of interest to know that in the laundry of the Queen’s 
palace, all fabrics of vegetable origin are treated with a solution 
of neutral sodium tungstate of 28° Tw. containing three per cent, 
of sodium phosphate. This solution is added to the starch also 
when the latter is employed. 

Abel’s researches 2 show that in naval warfare, calcium chlo¬ 
ride is valuable to protect rope mantelets, while canvas is well 
protected by stannic oxide and still better by the double silicate 
of sodium and lead. 

The efficacy of sodium tungstate, as well as of the ammonium 
salts, for the scenery and decoration of theaters, has also been 
firmly established. 

The comparative results of Eochtin’s experiments on pure cel- 

1 F. Fischer, Ding. poly. Jour., 245, 36. 

2 Arner. Arch., 13 and 14. 


30 


THOMAS H. NORTON. METHODS OF 


lulose* may well be summarized here as they offer a valuable 
classification and furnish useful hints ; although it must not be 
forgotten that the tests were elementary in their nature, and the 
conclusions,. hence, open to criticism, as is, in some cases, evi¬ 


dent. 


Lochtin divides compounds into three classes, with reference 

to the effects on combustibles, (i) The 

antipyrenes, which 

render cellulose uninflammable when present 

in relatively small 

amounts, and when used in weak solutions. 

(2) Indifferent sub- 

stances which are effective only when present 
(3) Substances which favor combustion. 

in large amounts. 

I. 

ANTIPYRENES. 


Quantities of anhydrous substances required to render cellulose 


u n infla m m a b le. 



Minimal strength of 
solution used in 

Minimal relative 


weight (cellu¬ 


per cent. 

lose — IOO'},. 

NH 4 C1 

i*5 

4.2 

(NH 4 ) 2 HPO s 

M 

4-5 

(•nh 4 ),so 4 

1.5 

4-5 

ZnCl 2 

i-5 

4.0 

CaCl 2 

i-5 

4-5 

MgCfj 

i-5 

4-5 

A1 2 (OH) s 

i-5 

3- 8 

KA1(S0 4 \ 

2.0 


ZnS0 4 

U5 

4-5 

SnCl., 

2.5 


Na,B 4 0 7 

i-5 

8-5 

B,>6, 

2-5 

10.0 

II. INDIFFERENT SUBSTANCES. 

HKO 

7-5 


MgS0 4 

7-5 

IS 

NaCl 

7-5 

35 

Na 2 SiO'. ? 

17-5 

50 

SiO., 

12.5 

30 

Kd 

20.0 

45 

Na 2 HP0 4 

7-5 

30 

k 2 hpo 4 

20.0 


A1 2 3(B 4 O y > 

12.5 

24 

aipo 4 

10.0 

30 

Ca 3 2(P0 4 > 

12.5 

30 

MgHP0 4 

12.5 

30 

ZnB 4 0 7 

7-5 

20 

ZnHP0 4 

15+ 

.. 

WO, 

10-b 

15 + ' 

Na 2 W0 4 

10-f- 

15+ 

(NH 4 ) 2 W0 4 

7-5 

io 4 - 

day (air dry) 


75 

NaC 2 H 3 0 2 and KC,H,0 2 7.5—5 



1 Ding, poly. Jour., 290, 230.- 


PREVENTING AND EXTINGUISHING CONFEAGRATION. 3 1 

III. SUBSTANCES FAVORING COMBUSTION. 

Na 2 S 0 4 , Na 2 S 0 8 , Na 2 C 0 3 , Na 2 SnO s , Mg(OH) 2 , K 2 S 0 4 , 
Z11CO3, CaC 0 3 , MgC 0 3 , CaS 0 4 , FeS 0 4 . 

In reviewing the above tables, it is of importance to note that 
the aluminum hydroxide used is that obtained by double decom¬ 
position between sodium aluminate and sodium bicarbonate. 
The product formed by the action of ammonia on aluminum sul¬ 
phate is of no value. It will be seen, also, that the somewhat 
expensive sodium tungstate is much less effective than many 
other compounds, the chemical nature of which debars them, 
however, from ordinary application. Thus, (apart from cost), 
acid or alkaline reaction, difficulty in solution, hygroscopic 
properties, or readiness to decompose, on contact with hot iron 
or otherwise, handicap, as it were, most of the antipyrenes. The 
chief value of Uochtin’s work is to be found in the recognition of 
aluminum hydroxide as so pronounced an antipyrene and the 
fixing of the conditions under which it is deposited in the most 
effective form. 

The most important and decisive results with regard to the 
efficiency of the different current protectives of wood are fur¬ 
nished by Boudin and Donny. 1 Using a classification based 
upon their rigorous and conclusive tests, we can arrange the 
protectives in the following series, ascending from the least 
effective to the most effective. 

I. PREPARATIONS OF EITTEE VAEUE. 

1. Injection of sodium tungstate (56 kgms. per m 3 ). 

2. “ “ copper sulphate 20 “ “ 

3. “ “ calcium chloride 50 “ “ 

4. “ of ammonium chloride 48 “ “ 

5. Coating of waterglass (43 per cent, solid residue), 1 coat, 

286 grams per m 2 . 

6. Coating of waterglass and zinc oxide, 4 coats, 1 kgm.perm 2 . 

7. “ “ Martin’s ignifuge, No. 4, 2 coats, 450 grams per nr. 

8. “ “ Brocher’s preparation, 3 “ 

9. “ “ Blane’s asbestos paint, 2 “ 1 kgm. perm 2 . 

10. “ “ cyanite (basic aluminum silicate), 2 coats, 450 

grams.per in 2 . 

1 Rapport. 


32 


THOMAS H. NORTON. METHODS OF 


II. PREPARATIONS OF SOME VAEUE WHICH EESSEN, IN A 
MARKED DEGREE, THE INFEAMMABIEITY OF WOOD. 

11. Covering of cyanite, 3 coats, 570 grams per m 2 . 

12. “ Bell’s asbestos paint, 3 coats, 820 grams per m 2 . 

13. “ waterglass 1 and ferric oxide,'4 coats, 700 grams 

per m 2 . 

14. Covering of waterglass’ and powdered glass, 6 coats, 900 
grams per m 2 . 

15 Covering of waterglass’ (undiluted), 2 3 coats, 475 grams 
per m 2 . 

III. PREPARATIONS OF THE HIGHEST EFFICIENCY WHICH PRE¬ 
VENT ALMOST ENTIRELY THE PROPAGATION OF FIRE IN 
WOOD. 

16. Covering of the United Asbestos Co. paint (waterglass, 
sodium aluminate and asbestos), 3coats, 850grams per m 2 . 

17. Injection of ammonium phosphate, absorption of 75 kgms. 
per m 3 after boiling for twelve hours in a sixteen per cent, 
solution of the salt. 

These two protectives would seem therefore the high-water 
mark of what chemists have attained in their efforts to render 
wood inflammable. With regard to the permanence of their pro¬ 
tective power, it has been observed that, after the lapse of two 
years, wood treated with the asbestos preparation had lost, in no 
measure, its resistant qualities, while that injected with ammo¬ 
nium phosphate showed an exceedingly slight diminution in the 
efficiency. No diminution was noticed at the end of nine months 
in the resistance of injected wood, kept at ordinary temperature, 
or at 45 0 C., or covered with a coat of oil-paint. It should be 
noted also that the solution of ammonium phosphate does not 
affect nails and other objects in iron even after contact for several 
months ; also that the solutions of the salt must be nearly satu¬ 
rated in order to yield satisfactory results. 

Boudin and Donny’s experiments would tend to indicate a 

1 In all these tests a waterglass of forty-three per cent, solid residue was used. It 
was generally diluted with water, but this additional water is not included in the 
weight per m2. 

2 Wood, when first covered with waterglass, presents a varnished appearance. 
This is not retained long, as the coating soonbegius to scale, and the surface is covered 
with a white efflorescence. 


PREVENTING AND EXTINGUISHING CONFLAGRATION . 33 

slight lessening in the strength of wood which has been injected. 
The general conclusions drawn from their investigations are: 

1 • ^he incombustibility of wood, z. e ., its non-alteration when 
under the influence of heat, cannot be attained. It is possible, 
however, to secure its non-inflammability, so as to preserve ordi¬ 
narily any structure exposed to an accidental fire, or at least to 
allow time for the arrival of the ordinary extinguishing appli¬ 
ances, unless it be filled with combustible material. 

2. Of the preservative processes used, injection of saline solu¬ 
tions or the application of protective coverings, the former would 
seem ill adapted for timber of large dimensions, but of manifest 
value for the less bulky forms of wood. In all such cases the 
use of ammonium phosphate, in saturated solution, offers such 
incontestable advantages, that, despite its high price, it should 
be employed unless excluded absolutely by limitations of ex¬ 
pense. (Ammonium phosphate can be obtained for about $50 
per 100 kgms., and as a cubic meter of wood absorbs seventy- 
five kgms., the cost per cubic meter would be about $38.) 

3. In the majority of cases protective coatings are preferable. 
The most efficacious is that containing sodium aluminate and 
asbestos in waterglass, while waterglass alone, or with the addi¬ 
tion of aluminum hydroxide, is of great value. 

EXPLANATION OF THE ACTION OF PROTECTIVES. 

Such being the practical results attained, it is of interest for 
us next to know in just what way these chemical compounds act 
to prevent inflammability. It is, in fact, a matter of surprise 
that the experimentation in this field has been so largely empir¬ 
ical, neither preceded nor followed by theoretical considerations. 

In studying the effects of heat on ordinary wood, the following 
will be noted: 1 When exposed for some time to a temperature 
of 200 0 C., wood becomes light brown and its strength is materi¬ 
ally affected. At 300° it is charred completely, losing all power 
of resistance, but still without a trace of flame. If, however, the 
wood be in contact with flame, or be exposed to a red heat, 
change takes place rapidly, and if air have free access it bursts 
into flame, and combustion does not cease until the entire mass 
be reduced to ashes. 

1 F. Fischer, Ding. poly. Jour., 245, 36; Boudin et Douny, Rapport. 


34 


THOMAS H. NORTON. METHODS OF 


When wood protected by a suitable coating, such as water- 
glass, is exposed to a temperature of 200° C., it acts exactly as 
ordinary wood. Wood, however, which has been injected with 
saline solutions, as ammonium phosphate, is more liable to 
change. It assumes a deep. brown tint, and the resistance to 
strain is greatly lessened. At 300° all forms of protected wood 
are carbonized, exactly as the ordinary wood, and without flame. 

At a red heat, or in contact with flame, prepared w 7 ood is com¬ 
pletely destroyed; but there is a vast difference between its 
rate of destruction and that of non-protected wood. At first 
there is a pronounced period of direct resistance. Jn cases where 
external applications have been made, the heat gradually pene¬ 
trates the protective coating, jets of gas issue through fissures 
in it, and, their,combustion contributes to the intensity of the 
surrounding sources of heat, until, finally, combustion is com¬ 
plete. In the case of wood impregnated with suitable saline 
solutions,, resistance to the flame is likewise marked, but much 
gas is evolved. This gas is not inflammable but seems, on the 
contrary, to interfere seriously with the combustion of the sur¬ 
rounding fire. Complete charring is finally reached. It is evi¬ 
dent in both cases that the ordinary effects of heat upon wood 
are seriously hindered or retarded. The first effect of heat, as 
we have seen, is to produce gas and leave carbon. This gas, if 
allowed to burn with the oxygen of the air, furnishes a fresh 
supply of heat to bring about further evolution of gas. But as 
organic matter and the resultant charcoal are both poor conduc¬ 
tors of hea!t, gasification would proceed very slowly unless the 
coal on the surface also changed to gas by burning with atmos¬ 
pheric oxygen (as well as by reducing the carbon dioxide and 
water present), thereby increasing the available temperature. 
The maintenance of a sufficiently high surrounding temperature 
must eventually cause the penetration of enough heat into the 
body of wood exposed to produce complete gasification and car¬ 
bonization, and finally complete combustion of the charcoal. 
This action can be retarded evidently by two distinct agencies. 
The first is the evolution of an inert or non-combustible gas or 
vapor from the wood through the influence of heat; the second 
is the presence of an external coating, which is not only a poor 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 35 

conductor of heat, but also protects the outside zone of charcoal 
from contact with atmospheric oxygen. It is in one or both 
directions that fire protectives render service. 

The ammonium salts are good types of the first class. Ammo¬ 
nium chloride and ammonium sulphate are readily vaporized 
and dissociate, the first into ammonia and hydrochloric acid, 
the second into ammonia, nitrogen, water, ammonium, sul¬ 
phite, etc. Ammonium phosphate decomposes slowly to meta- 
phosphoric acid (sixty-two per cent, of its weight), ammonia, 
and nitrogen monoxide. It is probably this slowness of decom¬ 
position which renders the phosphate superior to the other ammo¬ 
nium salts. In the case of magnesium chloride, zinc chloride, 
etc., hydrochloric acid is driven off. In the case of other salts, 
such as the alums, the borates, copper sulphate, and sodium 
tungstate, large amounts of water of crystallization are neces¬ 
sarily liberated in the form of aqueous vapor. It is a matter of 
surprise that this fact, that the storage of considerable amounts 
of water in the solid form in the interior of wood is a potent fac¬ 
tor in the protective value of a number of antipyrenes, should 
have escaped the attention of chemists. It is an easy matter to 
calculate the volume of aqueous vapor capable of being formed 
from a given weight of Na 2 B 4 0 7 -f- ioH 2 0 or Na 2 W 4 0 13 + ioH 2 0 
or K 2 Al 2 (S 0 4 ) 4 -f- 24H 2 0. There is no question but that such 
salts, as the above, retard the attack of flame chiefly through 
this agency at first, although after the expulsion of the water of 
crystallization, the presence of the saline substance coating the 
charred surface and acting as a poor conductor of heat, as well 
as preventing the access of oxygen, continues the protection for 
a certain time. It is in the varying ability of different com¬ 
pounds to form coherent, continuous protective coatings after 
exposure to heat that we find the reason of the superiority of one 
composition, for external application, over another. Thus, 
waterglass alone gives good results. When wood treated with 
it is heated, we notice a puffing out and swelling, a certain 
amount of vapor escapes, and the residue is left as a light, 
voluminous, fairly coherent covering, through which air can 
penetrate but slowly to the charred surface beneath, and heat is 
likewise conducted but slowly. The addition of aluminum 


36 


THOMAS H. NORTON. METHODS OF 


hydroxide to the waterglass seems to increase the resistant prop¬ 
erties of this envelope, while the further addition of asbestos and 
the substitution of sodium aluminate for aluminum hydroxide, 
forming thereby practically a quadruple silicate of sodium, mag¬ 
nesium, calcium, and aluminum, give the highest resistant 
power. 

It may be pertinently inquired, why does the presence of some 
salts seem apparently to help combustion ? Lochtin explains this 
action 1 by the uneven distribution of some substances during 
drying or precipitation, more, proportionately, remaining on the 
surface of the paper or wood used. Here they form porous but 
slightly compact crusts; and these favor continued glowing or 
combustion by preventing a loss of heat. 

PRACTICAE APPEICATION OF THE KNOWEEDGE GAINED. 

With this exposition of the results attained in the contest with 
fire—the fruit almost exclusively of the work of European chem¬ 
ists—what should be the practical application of the knowledge 
gained to our own conditions in America ? It is evident that there 
should be a rigorous insistence on the use of protective agencies 
for all wood employed in buildings containing material of per¬ 
manent value, such as deposits of archives, museums, libraries, 
etc. Equally rigorous should be the requirement in the con¬ 
struction of exhibition buildings; of churches, theaters, and all 
structures wherein large assemblages are held; of the stands 
about our fields for athletic amusements; of cars and craft for 
transportation by land or water; and above all, of the edifices 
of our institutions of learning. 

The applications enumerated above are nearly all easily 
within the reach of legislative enactment, as they affect the 
interests or lives of the public. 

How far the use of protective agents may be introduced into 
ordinary construction, and into household equipment it is diffi¬ 
cult to say. 2 In England the custom of protecting wearing 
apparel of vegetable fiber is widespread. No reason exists why 
American women, earnest in reform, should not advocate a 


1 Ding . poly. Jour., 290, 230. 

2 Ding. poly. Jour.. 245, 36. 


i 


PREVENTING AND EXTINGUISHING CONFLAGRATION. 37 

similar custom here. There* is no question, however, but that 
great stress should be laid upon the wisdom of impregnating the 
curtains, draperies, and hangings of our homes. 

It is to be hoped that the slow burning principle may soon be 
extended to domestic architecture, but even with our present 
methods, it is easily possible with the outlay of a few per cent, 
on the cost of the house to lessen enormously its fire risk. All 
beams, joists, studding, etc., which are later to be hidden, can 
be coated during the process of erection. Siliceous coatings can 
also be applied to all surfaces outside and inside which are ulti¬ 
mately to be painted. Finally, woods to be used for interior 
finish can be protected by steeping in a solution, preferably of 
ammonium phosphate, if not of one of the cheaper antipyrenes, 
before being varnished. Such a house, if isolated, and presup¬ 
posing the use of wire lath, is practically fireproof in nineteen 
out of twenty cases of ordinary conflagration. If provided with 
brick walls and slate roof, the risk is greatly lessened, and it is 
not difficult to recognize that blocks or districts of such con¬ 
struction are free from all danger of conflagration : that, in fact, 
fire will be confined exclusively to such rooms or houses as may 
be used for the storage of combustible material. Insurance, 
under such conditions, approaches almost the vanishing-point; 
and the freedom of apprehension from loss by fire is not to be 
measured by dollars and cents. We are here entering upon the 
proper province of another science. The chemist has provided the 
means of coping successfully with the dangers of combustion. 
It is for the economist to insist on the utilization of his achieve¬ 
ments, in assuring increased comfort and security to society. 
Suffice it only to add that existing structures may, to a great 
extent, be protected especially for those few precious minutes 
between the discovery of a fire and 'the arrival of aid, by the 
generous application of the siliceous compositions to all exposed 
woodwork. The direct value of such treatment has been 
promptly recognized in England by a decrease of fifty per cent, 
in the insurance rates on houses so treated. 

FIELD FOR FURTHER INVESTIGATION. 

Finally, what remains for the chemist to do in this field ? 


38 


THOMAS H. NORTON. METHODS OF 


Indirectly he may accomplish much in lessening the fire risk. 
First in the study of illuminants. Whatever tends to displace 
the use of petroleum for domestic lighting tends, by so much, to 
diminish the national fire bill, as this one substance is a most 
prolific cause of conflagration. It is to be hoped that the way 
may be opened to an economical and convenient use in this con¬ 
nection of our vegetable oils, now so abundant; or to the intro¬ 
duction of a fuel-gas saturated with hydrocarbons, so safe and 
economical that it may be promptly accepted for domestic light¬ 
ing. The possibilities offered in this direction by the extended 
utilization of calcium acetylide are also most hopeful. Next 
there is little doubt but that the early approach of the era 
of cheap aluminum will effect an important revolution in 
the use of structural materials, the light, unchangeable metal 
tending to displace wood in many of its external and internal 
applications. In this field American chemists have taken the 
lead. 

With regard to the production of new protectives it is hardly 
probable that the last word has been said. We have seen how 
experiment, beginning with sodium silicate, led successively to 
the addition of aluminum hydroxide, of lime, of lead salts, of 
powdered glass, and of finely divided asbestos to the convenient 
syrupy medium. 'There is but little doubt that other combina¬ 
tions, less expensive or more effective than those now in vogue, 
await the experimenter. 

The high rank of aluminum hydroxide among protectives, as 
shown by Eochtin, should lead to extended research with regard 
to its availability under different conditions, and its most eco¬ 
nomical application. 

The utility of magnesium borate, so warmly recommended by 
Patera and Fischer, should be definitely established by compara¬ 
tive tests. It is not unlikely that combinations of the borates 
and silicates may also be found to render good service. Experi¬ 
ments on the deposition of insoluble tungstate in fabrics are also 
worthy of being carried out. 

With regard to protection, by impregnation, it is doubtful 
whether any better agency than ammonium phosphate can be 


y 


/ 


/ 


f 



, ./ 

.tG CONFLAGRATION. 39 


yd. It would, Ilv> 


^visable to study the econom¬ 


ical production of this salt >he purpose in question. Might it 
not be possible to attain cheapness by using successive baths of 
ammonium sulphate and sodium phosphate ; or could not acid 
calcium phosphate be brought advantageously into the reaction ? 

A further field of investigation is the possible combination of 
injection and painting, impregnation with such deliquescent 
chlorides, as zinc chloride, or magnesium chloride, being fol¬ 
lowed by a simple external coat of a siliceous paint. Then the 
most favorable time for injecting or steeping wood with saline 
solutions should be definitely ascertained. Is it, after completed 
seasoning, or when the wood is perfectly green, as advocated by 
Jones ? 

The question of the most economical combination of protec¬ 
tion against fire and of preservation from decay and insect 
attack, remains also to be settled. 1 Another important phase is 
the highest attainable efficiency, from the use of salts which 
store up, in wood, considerable amounts of water of crystalliza¬ 
tion, such as gypsum ; for it must be borne in mind that every 
volume of solid water of crystallization yields 1700 volumes of 
aqueous vapor at ioo° C. 

It is largely along these lines that we may expect to see ad¬ 
vance made in the province whose survey we now complete. 

In conclusion, let me express the earnest hope that individu¬ 
ally and collectively the influence of this Association may be 
helpfully thrown in favor of any general effort to lessen our trib¬ 
ute to fire. We have made ourselves felt in movements to com¬ 
bat the twin, although antithetic, evils of drought and flood by 
the preservation and extension of our forests, as well as in other 
economic directions. Can we not do the same in availing our¬ 
selves of the work of Gay Lussac, Fuchs, Versmann, Oppen- 
heim, Abel, Tessier, Patera, and other chemists, by bringing 
into the American home and the American community that 
peaceful security and liberation from a dreaded tax, which 
comes with the practical abolition of danger from conflagra¬ 
tion? 

1 Rymer-Jones, Eel. Eng. Mag., 33 ^ 55 . 1885. , 










1 













. 




































i' 


0 033 266 496.7 











